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ZTF Spots Asteroid with Shortest Year 2019 LF6

ZTF Spots Asteroid with Shortest Year

Astronomers have spotted an unusual asteroid with the shortest “year” known for any asteroid. The rocky body, dubbed 2019 LF6, is about a kilometre in size and circles the sun roughly every 151 days. In its orbit, the asteroid swings out beyond Venus and, at times, come closer in than Mercury, which circles the sun every 88 days. 2019 LF6 is one of only 20 known “Atira” asteroids, whose orbits fall entirely within Earth’s.

“You don’t find kilometre-size asteroids very often these days,” says Quanzhi Ye, a postdoctoral scholar at Caltech who discovered 2019 LF6 and works with Tom Prince, the Ira S. Bowen Professor of Physics at Caltech and a senior research scientist at JPL, and George Helou, the executive director of IPAC, an astronomy center at Caltech.

“Thirty years ago, people started organizing methodical asteroid searches, finding larger objects first, but now that most of them have been found, the bigger ones are rare birds,” he says. “LF6 is very unusual both in orbit and in size—its unique orbit explains why such a large asteroid eluded several decades of careful searches.”

2019 LF6 was discovered via the Zwicky Transient Facility, or ZTF, a state-of-the-art camera at the Palomar Observatory that scans the skies every night for transient objects, such as exploding and flashing stars and moving asteroids. Because ZTF scans the sky so rapidly, it is well-suited for finding Atira asteroids, which have short observing windows.

“We only have about 20 to 30 minutes before sunrise or after sunset to find these asteroids,” says Ye.

To find the Atira asteroids, the ZTF team has been carrying out a dedicated observing campaign, named Twilight after the time of day best suited for discovering the objects. Twilight was developed by Ye and Wing-Huen Ip of the National Central University in Taiwan. So far, the program has discovered one other Atira asteroid, named 2019 AQ3. Before 2019 LF6 came along, 2019 AQ3 had the shortest known year of any asteroid, orbiting the sun roughly every 165 days.

“Both of the large Atira asteroids that were found by ZTF orbit well outside the plane of the solar system,” says Prince. “This suggests that sometime in the past they were flung out of the plane of the solar system because they came too close to Venus or Mercury,” says Prince.

In addition to the two Atira objects, ZTF has so far found around 100 near-Earth asteroids and about 2,000 asteroids orbiting in the Main Belt between Mars and Jupiter.

Ye says he hopes the Twilight program will lead to more Atira discoveries, and he looks forward to the possible selection by NASA of the Near-Earth Object Camera (NEOCam) mission, a proposed spacecraft designed to look for asteroids closer to the sun than previous surveys. NEOCam would pick up the infrared, or heat, signatures of asteroids. (Ye works at IPAC, which would process and archive data for the NEOCam mission, but is not part of that team.)

“Because Atira asteroids are closer to the sun and warmer than other asteroids, they are brighter in the infrared,” says Helou.”NEOCam has the double advantage of its location in space and its infrared capability to find these asteroids more easily than telescopes working at visible wavelengths from the ground.”

The International Astronomical Union Minor Planet Center listing for 2019 LF6 is at https://minorplanetcenter.net/mpec/K19/K19M45.html.

Materials provided by the California Institute of Technology

Meteor crater aerial view

Biggest asteroid crash in UK revealed by hidden crater

The biggest asteroid which is known to hit the British Isles is known to have slammed the Earth close to 1.2 billion years ago. However, experts have identified where the exact impact point may have been hidden for this whole time. The estimated spot is about 15 to 20 kilometres from the Enard Bay in the Minch Basin, between mainland Scotland and the Outer Hebrides. The study has been published in the Journal of the Geological Society.

The asteroid is expected to crash at about 65,000 kilometres per hour. There is no crater visible as of today and it is 200 meters deep in the ocean which is caked in layers and layers of sediment. The asteroid is thought to be one kilometre wide. The crater is predicted to be 13 to 14 kilometres wide and 3 kilometres deep.

Geochemist Ken Amor from the University of Oxford in the UK has said that the impact would have sent huge amounts of rolling clouds of dust and gas at several hundred degrees in all directions from the site.

During a field trip to the Scottish Highlands, the expedition included a study of the Stac Fada Member(SFM) where they noticed strange green blobs in the rock. These blobs are a sign that an asteroid strike took place. The samples were taken to the lab and were identified to be quartz crystals and metals like platinum and palladium which are well known as meteorite metals.

The team also analyzed the rock patterns as well as the orientation of the magnetic grains in the geographical area to pinpoint the area of the original site of the crash. Amor has said that if we imagine debris flowing out of a cloud across the area, hugging the ground, then eventually the material will slow down and come to rest. The clouds at the front will stop first and the ones at the back keep pushing forward until they stop which causes an overlap of layers in the front. Events such as these are known to happen once in a million years and as often as once in every 100,000 years.

The next process would be to conduct a complete geographical survey in the Minch Basin which would confirm the results as stated by the laboratory research. The material which is excavated from a meteor crash is rarely preserved by Earth as it gets eroded very rapidly by air and water. It was a purely coincidental discovery that this rock landed in an ancient valley and sediments quickly covered it and the debris was preserved.

Schematic view of asteroid Itokawa

New clues on origin of life found from water samples on Asteroid Itokawa

Water is a precious and limited resource yet humans have not valued it only until recent times where there is awareness about the shortage of water and global warming. Nowadays, a lot of research is going on to find traces of life outside the Earth and various space missions are held which have successfully found traces of water on the moon and Mars.

In 2010 however, Japan Aerospace Exploration Agency (JAXA) made history when its Hayabusa probe brought back samples from the Asteroid Itokawa, it was the first time mankind had gone to an asteroid, collected samples and brought it back safely to the Earth. After studying those samples a study was published in the Journal of Advanced Sciences that they contain lots of water inside them.

A cosmochemist at the Arizona State University, Maitrayee Bose had commented that no one really expected to find water samples on Itokawa as it was known that Itokawa asteroid faces temperatures up to 1500 degrees Fahrenheit and faces many collisions in space in the voyage. So there wasn’t much hope to find traces of water until we did a lot of calculations which showed that indeed it might be possible. Itokawa is a 1,800 foot long and 1,000-foot wide satellite which orbits the sun every 18 months, Itokawa was an asteroid which was remains of a bigger asteroid close to 12 miles long. The research done by Bose aims to study the internal chemistry of small building blocks for life. He is interested in finding out whether asteroids and other eternal bodies are able to deliver water and organic chemicals to other planets, and also find planets with the existence of water other than our Earth.

The samples from the JAXA which were brought back to Earth contained 5 samples which were half as thick as the sample of hair. Two of these samples contained mineral pyroxene. Pyroxenes contain water as a part of their crystalline structure and which then suspected Itokawa to contain water. To study these samples which were half the thickness of the strand of hair, the team used ASU’s Nanoscale Secondary Ion Mass Spectrometer (NanoSIMS), which can measure such tiny mineral grains with great sensitivity.

The results showed the presence of water and those relatively dry asteroids like Itokawa can also contain traces of water. Itokawa is an S-class satellite based on its spectrum. Bose further added that S – class satellites are most common objects in the asteroid belt and although they are small and have contained water and other volatile minerals which they are made up of. The race for exploration of water and life is heating up between countries and for the good of humanity.

Asteroid Apophis Closest Approach To Earth

A 1100 ft wide asteroid to pass by Earth within a decade

According to reports from NASA, a huge asteroid will be visible to the human eyes when it passes the Earth at a very close distance, equal to the heights at which spacecraft orbit the Earth.

The asteroid is named 99942 Apophis, measuring 1100 ft wide. It will be passing the sky like a bright star-like point of light and will gain in brightness and velocity on Friday, 13 April 2029.

At a distance of 19000 miles from the surface of Earth, it will be visible to the human eyesight. The residents of Southern Hemisphere will be able to observe it first, namely the eastern and western coasts of Australia.

After that, it will be moving across the Indian Ocean and will be crossing the Atlantic Ocean in an hour’s duration, finally passing by the United States in the evening.

It is very rare for an asteroid of this dimension to cross Earth so closely. According to NASA, there have been smaller asteroids of 10-20 metres which have passed the Earth at very similar distances but those of the size of Apophis have been rare.

The observation and scientific opportunities related to this event were discussed by scientists at NASA at the Planetary Defence Conference 2019 which was held in Maryland.

Scientists have calculated that the asteroid will cover a distance which is more than the width of the full moon in the duration of only one minute and its brightness will be comparable to that of the stars in the Little Dipper constellation.

Marina Brozovic, a radar scientist who works at NASA’s Jet Propulsion Laboratory situated in Pasadena, California commented that the close approach of the asteroid Apophis in 2029 will be a very exciting opportunity for the scientific world. She also said that the observations will be made with both optical and radar telescopes.

With the help of radar observations, it might be possible to view the details of the surface which are only of a few metres in size.

The asteroid Apophis was discovered on 19th of June, 2004 by a group of researchers that included Roy A. Tucker, David J. Tholen, and Fabrizio Bernardi. It was detected at the Kitt Peak National Observatory. The name Apophis is the Greek name of Apep, the enemy of Sun God in Egyptian Mythology.

When initially found, researchers detected the chance of the asteroid hitting Earth at a probability of 2.7% in 2029. However, the latest calculations show that the asteroid may hit our planet at a chance of 1 in 100000, several decades later.


Scientists detect presence of water in dust particles from asteroid Itokawa

Researchers have detected presence of water in grains of dust obtained from the asteroid Itokawa. This finding can be a important clue on how water formed in Earth. The studies have been published in the journal Science Advances.

The peanut shaped asteroid, Itokawa was found in 1998 by LINEAR, a collaboration of NASA with United States Air Force. It has been named after Japanese engineer, Hideo Itokawa. It has a very low density and has a rotation time of 12 hours.

A team of researchers from Arizona State University has measured the quantity of water in the small particles of dust which were carried to earth by the Japanese spacecraft, Hayabusa. Hayabusa, a robotic space probe is manufactured by the Japan Aerospace Exploration Agency for studying the elements, characteristics of Itokawa. It started its journey, collected more than 1500 regolith particles and returned back to Earth in 2010. Though this is not the first evidence of presence of water in an asteroid, scientists have detected water for the first time in laboratory. In other cases, it was done with the help of information collected by telescopes or the equipments present in the spacecrafts.

The first proof of water in asteroid was found in 2010 when scientists used Infrared Telescope Facility of NASA to detect water ice on the asteroid Themis. Also in December, 2018 scientists detected hydrated minerals while studying the rocks of the asteroid Bennu. After these discoveries, scientists have come to the conclusion that presence of water is quite common in our solar system. It may be present either in the form of water ice or hydrated minerals.

From the current findings, the scientists at ASU have concluded that the silaceous asteroids like Itokawa , which are stony asteroids composed of silicates and also one of the most frequently found rocks in space might have delivered almost half of Earth’s water during its formation.

Ziliang Jin, researcher at School of Earth and Space Exploration at ASU along with fellow cosmochemist Maitrayee Bose calculated the abundance of water along with the percentage composition of deuterium and hydrogen, a factor which can indicate the similarity of the water to the water found on Earth. It has been found that the composition of isotopes of hydrogen are similar to Earth.

The team at ASU received five samples out of the 1500 ones brought by spacecraft Hayabusa. Each one measured about half of width of human hair. They have been obtained from the Moses Sea, lying in the middle of the asteroid Itokawa.